1. Field of the invention
The present invention relates generally to a keyswitch, and more particularly, to a keyswitch with a balance member.
2. Description of the prior art
Generally, the keyswitch used in computer keyboard is constructed of a keycap, a substrate, and a scissors-like support disposed therebetween to support the keycap moving vertically opposite to the substrate. Moreover, when the keycap is moved downward to the substrate, it can trigger a switch disposed on the substrate. Said support has been fully disclosed in certain patent applications, as discussed in Taiwan Patent Number 319,438, entitled “Keyswitch with scissors-like support”. The above-mentioned structure is mainly suitable for square keyswitch. However, a balance member is needed for a longer keyswitch or a keyswitch with special shape (such as multiple key or functional keyswitch “space”, “shift”, or “enter”) to prevent said keyswitch tilt when a user presses on the edge of said keyswitch.
In the prior art, such as Taiwan Patent Number 346,213, entitled “Improved structure of multiple key”, and Taiwan Patent Number 411,004, entitled “Improved structure of balance member of multiple key”, the above-mentioned balance member is designed as U shape to perform said functionality. Please refer to FIG. 1A, which illustrates the keycap and the balance member of the prior art. As shown in FIG. 1A, the balance member 52 is engaged with the fixing portion 504 of the bottom surface 502 of the keycap 50.
However, in practice, the keycap of the multiple key may be designed as a trapezium, a triangle or other polygon. Please refer to FIG. 1B, which shows the keycap and the balance member in the prior art. As shown in FIG. 1B, the appearance of the keycap 70 is substantially a trapezium. Accordingly, the conventional U-shaped balance member 72 can not cover the whole keycap 70. Moreover, when an user presses on the edge (e.g. the portion marked with the dotted circle may tilt as mentioned above) of said keycap 70, the keycap 70 may tilt, and the balance member 72 may even fail to drive the movement of the keycap 70 and further fail to trigger the switch disposed on the substrate.